Edge sensing device



April 1966 G. HENDERSON 3,244,418

EDGE SENSING DEVICE Filed Nov. 26, 1965 2 Sheets-Sheet l INVENTOR: Aim/25s GAGA/052w ATTORNEY April 5, 1966 J. G. HENDERSON EDGE SENSING DEVICE heats-Sheet 2 Filed Nov. 26, 1963 INVENTOR aiwoifism) BY ATI'ORN EY United States Patent 3,244,418 EDGE SENSING DEVICE James G. Henderson, R0. Box 92, Dalton, Ga. Filed Nov. 26, 1963, cm. No. 325,878 11 Claims. (Cl. 271-59) This invention relates to an edge sensing device for sheet material, and more particularly, to a pile edge fol lower. One object of this invention is to provide an edge sensing device, which is not only adapted to follow the edge of a sheet or web, but also to locate the edge.

Another object of this invention is to provide a pile edge follower which is adapted to compensate for varying pile heights and thicknesses.

A further object of this invention is to provide an edge sensing device for sheet material, which is not only adapted to guide the edge to a given point or along a given line, but which may also be adapted to guide any other device or object to the edge of the sheet material.

Another object of this invention is to provide a novel electronic circuit responsive to the movements of the edge of a sheet or web, such as a pile edge, for automatically controlling the position of the edge.

A further object of this invention is to provide a novel electronic circuit having an adjustable time delay for varying the degree of sensitivity in an edge sensing device.

' Another object of this invention is to provide a novel pile edge sensing device incorporating a pair of electrical switch fingers adapted to normally ride on top of the pile, and a second pair of switch fingers normally adapted to ride on the selvage of the .pile fabric for sensing and guiding the pile edge.

A further object of this invention is to provide a novel actuator or follower finger for use in a pile edge follower, or sensing device.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings, wherein:

FIG. 1 is a fragmentary rear elevation of the tion operating upon a pile fabric;

FIG. 2 is a schematic electrical diagram of the electronic control circuit for one pair of the actuators;

FIG. 3 is an enlarged section taken along the line 33 of FIG. 1 showing the normal inoperative positions of the actuators or follower fingers;

FIG. 4 is a section taken along the line 44 of FIG. 3;

FIG. 5 is a section taken along the line 55 of FIG. 4;

FIG. 6 is a front elevation of the actuators disclosed in FIG. 3; and

FIG. 7 is a top plan view of the actuators disclosed in FIG. 3.

One form of sheet material upon which the sensing device may operate is a pile fabric 10 having a raised pile or tufted surface 11 and a selvage 12 extending laterally from the edge 13 of the pile surface 11. The pile fabric 10 is shown supported by a feed roll 15 having a shaft 16 freely journaled for both rotational and axial movement in a bearing 17 fixed to a frame or standard 18. The shaft 16 is rotatably driven by means, not disclosed. Shaft 16 is also journaled in a collar 20 for free rotation, but constrained to axial movement with the collar 20 by any convenient means, such as internal flanges, not shown. The collar 20 may be provided with a depending arm 21 having an internally threaded block 22 for engaging the elongated threaded end portion 23 of the motor shaft 24 driven by the reversible electric motor 25 of any convenient type. The motor 25 is controlled through the conductors 26 and 27 from electronic circuits within control box 28.

The edge sensing or follower device 30 includes four inven- 3,244,413 Patented Apr. 5, 196 6 actuators or follower fingers or arms 31, 32, 33 and 34, all of which are substantially the same shape, as disclosed in FIGS. 3 and 5, and all of which are pivotally supported for free rotatable movement about a common shaft 35. The shaft 35 may be fixed to a post 36 depending from a carrier 37, supported on wheels 38 on tracks 39 on a horizontal beam 40, fixed to the frame 18. The carrier 37 is provided with an internally threaded block 41 threadedly engaged by an elongated screw 42, which can be rotated in either direction by the hand wheel 43. Thus, by rotating the hand wheel 43, the sensing device 30 may be laterally adjusted to determine the predetermined position or line along which the edge 13 of the pile fabric 10 will be guided.

When the sensing device 30 is properly aligned, the actuator or follower fingers 31 and 32 will ride on top of the pile surface 11, while the pair of follower fingers 33 and 34 will ride on the selvage 12, as best disclosed in FIGS. 1, 4, 6 and 7.

An electrical contact or electrode 46 is fixedly mounted on the front edge of the finger or actuator 31 so that the contact 46 is located in the path of the front face 47 of the actuator 32. During the normal positions of the pair of actuators 31 and 32, as best disclosed in FIG. 5, the contact 46 is spaced from the front edge 47 of the actuator 32 to break electrical contact. However, the spacing between the contact 46 and the face 47 is such that when the actuator 32 drops from the pile surface 11 down upon the selvage 12, the actuator 32 will pivot counter-clockwise in FIG. 5 so that the face 47 will engage and electrically contact the electrode 46.

Another electrode or electrical contact 48 is also fixedly mounted on the rear edge of the actuator 31 so that it will move with and in a pivotal plane parallel to the actuator 31 on the opposite side from actuator 32. Fixed to the shaft 35 and extending rearwardly beneath and in the pivotal plane of the contact 48 is a contact arm 49, as shown in FIGS. 4 and 5. When the actuator 31 is normally riding on a pile surface 11, contact arm 49 is out of engagement with contact 48. However, when the actuator 31 drops upon the selvage 12, the contact 48 will immediately engage the contact arm 43.

Another electrical contact 52 is fixed on the front edge of the actuator 33 so that it is located in the path of the front face 53 of the actuator 34, as disclosed in FIG. 3. When actuator 34 is actually riding on the selvage 12, the front face 53 and contact 52 will be disengaged. However, when the actuator 33 rides upon the pile surface 11, it will rotate clockwise in FIG. 3 about the shaft 35 to pivot the contact 52 into engagement with the face 53.

Another electrical contact 54 is fixedly mounted on the rear portion of the actuator 34, but on the opposite side from the actuator 33. Another contact arm 55 is also fixed to and extends rearwardly from shaft 35, but above and normally out of engagement with contact 54, as disclosed in FIG. 3. However, if the actuator 34 should be raised for any reason, such as riding upon the pile surface 11, the actuator 34 will rotate clockwise in FIG. 3 about shaft 35 to pivot the contact 54 into engagement with the contact arm 55.

From the above description of the various actuators and electrical contacts, it will be seen that the actuators 31-34 and contact arms 249 and 55 act as electrical switches, any one of which will be closed when an actuator is not in its normal or original position disclosed in the drawings.

In order for the various switches to control the elec tric motor 25, a pair of identical electronic circuits are provided in the control box 28, one circuit for causing the motor 25 to drive in one direction, while the other circuit causes the motor to drive in the reverse direction. The electronic circuit 60 is energized by a pair of pile actuators 31 and 32 and the contact arm 42 as disclosed in FIG. 2. An identical circuit, not shown, is independently controlled by the pair of selvage actuators 33 and 34 and the contact arm 55.

The electronic circuit 6t? includes a vacuum tube 2 including an anode or plate 63, a grid 64 and a grounded cathode 655. A negative voltage is applied to one side of a potentiometer 56, the other side of which is grounded, and a negative grid voltage is picked off the potentiometer 66 through the grid circuit 67 including resistor 63. This grid voltage is regulated normally to shut off or stop conduction through the tube 62. Connected in parallel to the grid circuit 6'7 is a switch circuit 70 having a branch lead or circuit 71 connected to the contact 6 and a second parallel branch lead or circuit 72 connected to the contact of the actuator 32. A positive voltage is applied through lead 74 and the resistive plate circuit '75 to plate 63. The plate circuit 75 is connected through a relay 77 to the plate circuit 78 of a tube 75 having an anode or plate 8%, a grid 31 and a cathode 82. The negative voltage is applied through the circuit 83 to the oathode 82. The grid 81 is coupled to the cathode 82 through circuit 85 including in series, a capacitor 86 and a resistor 87. The grid 81 is connected to the plate 80 through circuit 88, including in series a resistor 89 and a potentiometer 90. Another circuit 92 coupling the grid 81 and the cathode 82 is in parallel with the circuit 85 and includes a relay 93, which when closed, also closes another relay 94 in the motor control circuit 26 and equalizes the potentials on the grid 81 and the cathode 82. In this particular arrangement, when the relay 94 is closed, the motor 25 will be energized to rotate the motor shaft 24 in a direction to move the collar 20, and consequently the shaft 16, feed roll 15 and the pile fabric 1% laterally toward the left as viewed in FIG. 1. In a second control circuit identical to 6d, when the motor relay is closed, the circuit 27 will be closed to energize the motor 25 to drive the shaft 2 1 in the opposite direction in order to move the fabric laterally toward the right, as viewed in FIG. 1. In the second circuit, the switch circuit 179 has one branch lead 171 connected to the contact 52 and another parallel branch lead 172 connected to the contact 54.

The operation of the invention is as follows:

Before the feed roll is started, the sensing device 31) is first laterally adjusted by turning the hand wheel 43 in order to set the sensing device at the desired location for establishing an imaginary guide line for the path of the pile edge 13. When the sensing device 3d is properly located, the actuators 31 and 32 are riding on top of the pile surface 11 with the actuator 32 closest to the edge 13, while the actuators 33 and 34 are both riding on the selvage 12 with the actuator 33 being closest to the pile edge 13. In this normal position, as disclosed in FIGS. 1, and 3-7, none of the electrical contacts 46, 48, 52 or 54, engage their opposing surfaces or arms 47, 49, S3 and 55. 7 Consequently, none of the switches in any of the switch circuits '70 or 170 are closed. With the switch circuit 70 open, a negative bias voltage is applied through the potentiometer 66 and the grid circuit 67 upon the grid 64 to shut oif, or stop, conduction through the tube 62. With the tube 62 shut off, the relay 77 remains open so that there is also no conduction through tube 72, and the relays 93 and '2 remain open. The condition of the other electronic circuit controlling the selvage actuators 33 and 3 1 is also the same, so that both motor circuits 26 and 27 remain open to maintain the motor 25 idle as long as the pile edge 13 remains moving along the same predetermined guide line.

However, if the pile edge 13 for some reason should drift laterally to the right in FIG. 1 sufficiently to cause the actuator 32 to drop off the pile surface 11 and rotate down upon the selvage 12, the front face 47 of the actuator 32, which is electrically grounded, will engage the contact 46 to close and thereby ground the branch circuit 71, the switch circuit 711 and consequently the grid 64 of tube 62. With the negative bias voltage upon the grid 64 eliminated, the tube 62 immediately beings to conduct to close the relay 77 and cause a positive voltage to be applied upon the plate 86 and upon the potentiometer However, the tube 79 will not begin to conduct, until the negative bias voltage on its grid 81 has been reduced through the RC time-delay circuit including capacitor 86 and resistor 89. The capacitor 86 being negatively charged, rnust first discharge through the resistor 89 and potentiometer 90, the discharge time depending upon the adjustable setting of the potentiometer 90. After capacitor 86 has completely discharged, the grid 81 becomes positive permitting the tube 79 to conduct to simultaneously close the relays 93 and 94 and thereby energize circuit 26 to move the fabric 10 toward the left until the actuator 32 has been restored to its original position upon the pile surface 19. At this point, the switch circuits 7% and 71 are reopened because the counter-rotating actuator 32 breaks contact between the surface 47 and the contact 46. When the circuit 76 is open, the negative bias voltage is restored to the grid 64 to shut off the tube 62, open the relay 77, shut off tube 79 and open the relays 93 and 94 to stop the motor 25.

If, for any reason, both actuators 31 and 32 should be riding upon the selvage 12, for example if the sensing device 30 were not originally set in its following position disclosed in the drawings, the actuators 31 and 32 will be in the same relative position to each other as if they were both riding on the pile surface 11, in which event the contacts 4d and 47 remain open and the control circuit 69 remains de-energized. However, when both actuators 31 and 32 are riding on the selvage 12, the actuator 31 is rotated downward to a position where the contact 48 engages the stationary contact arm 49, which is also electrically grounded. Thus, the branch circuit '72 is closed to ground the switch circuit 70 and energize the control circuit 60, in the same manner as the grounded branch circuit 71, to energize the motor 25 and move the fabric 11 toward the left in FIG. 1 until the actuator 31 engages the edge 13 and rides upon the pile surface 11. At this point, although contacts 48 and 49 are broken, contacts 46 and 47 will engage to continue the movement of the fabric 10 toward the left until the actuator 32 has also risen upon the pile surface 11. With the normal position of the actuators restored, the lateral shifting of the fabric 10 will automatically stop because all switches will be open.

On the other hand, if the fabric 10 has drifted to the left sufiiciently for the actuator 33 to rise and ride on the pile surface 11, the contacts 52 and 53 are engaged to close branch circuit 171 to ground the switch circuit 170 and thereby energize the corresponding control circuit, in the same manner as the control circuit 60, to close the motor circuit 2'7. The motor 25 is thereby reversed to counter-rotate the shaft 24 and drive the feed roll 15 and fabric 10 toward the right in FIG. 1 until the actuator 33 has returned to its original position, at which point the contacts 52 and 53 will open to de-energize the circuit 27 and stop the shifting of the feed roll 15.

If for any reason all four of the actuators 31-34 are riding on the pile surface 1d, the contacts 52 and '53 will remain open, but the upward rotation of the actuator 34 will cause the contact 54 to engage the fixed grounded contact arm 55 to close the branch circuit 172, which will also energize the motor circuit 27 to shift the pile fabric 10 toward the right in FIG. 1 until the actuators have been restored to their original position.

By adjusting the potentiometer in the time delay circuits 86, 89 and 90, the conductance of the tube 79 can be delayed so that momentary or periodic conduction through the tube 62 will not close the relays 93 and 94, and therefore the sensing device 31 will not be sensitive to slight or minor irregularities or deviations of the pile edge'13 from the original guide line. The potentiometer 90 can also be adjusted in the opposite direction to make the device 30 quite sensitive. I

The utilization of a pair of pile sensing actuators 31 and 32 and a pair of selvage actuators 33 and 34 permits the device 30 to operate independently of the height of the pile 11 above the selvage 12. Thus, the device 30 may be used upon different pile fabrics having difierent uniform pile heights, or it may be employed without being affected by varying pile heights in the same fabric. Thus, it is only the difference in the relative positions of each actuator in a pair 31-32 or 3344, which will close the corresponding circuit 26 or 27 to energize the motor 25.

It is also within the scope of this invention to employ the sensing device 30 to shift a device toward and away from the edge 13, other than the fabric support, for example, the cutting blade of a selvage trimmer. The controls would be the same, except the motor 25 would drive the cutting blade to be mounted upon a collar similar to 20 for shifting toward and away from the edge 13 by means of the rotation and counter-rotation of motor shaft 24. 7

It should also be understood that this invention is not limited to the particular electrical motor 25 and associated apparatus for shifting the feed roll 15, but may also include other types of electrical, mechanical, hydraulic, pneumatic or combination devices for shifting the fabric support.

Thus, it is apparent that a sensing device has been disclosed in which the edge of a sheet material, and particularly the pile edge of a pile fabric may be followed and/ or located in order to either shift the fabric to restore it to an original position, or to shift a device for operating upon the fabric to a predetermined position, regardless of the characteristics of the sheet or pile, such as its composition, color, position or height. The versatility of the sensing device is also increased by the novel electronic circuit 60, which permits varying degrees of sensitivity, adjustable to suit the requirements of the process.

Moreover, the shape and mounting of the actuators 31-34 with the curved bottom surfaces, permit the actuators to ride lightly with a minimum of frictional con tact and wear upon the pile fabric 10. Also, the curved bottom edges of the actuators 31-34 and their length and position relative to the pivotal shaft 35 is such that a fine adjustment is not required between the shaft 35 and the fabric support 15 for the sensing device to function efficiently. The bottom edges of the actuators may ride upon the respective fabric surfaces at any point along the curve, but preferably behind the pivotal shaft 35 so that the rearward movement of the fabric will not tend to bind against the actuators. The structure and pivotal mounting of the actuators 31-34 also permit them to operate in a variety of positions. For example, instead of the fabric 10 moving horizontally, it could be moved downwardly or upwardly without substantial adjustment of the actuators 31-34.

It will be further understood that all of the electrical contacts 46, 48, 52 and '54 are electrically insulated from the actuators.

It will be apparent to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof, and therefore the invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. An edge sensing device for a sheet having a longitudinal edge comprising:

(a) a carriage for supporting said sheet, for longitudinal movement substantially parallel to said edge,

(b) means for shifting said carriage laterally, inwardly or outwardly,

(c) an electrical control circuit for actuating said carriage moving means, i

(d) finger mounting means supported above said carriage,

(e) first, second, third and fourth follower fingers, pivotally mounted on said mounting means and spaced laterally of each other to pivot toward and away from said carriage and adapted to ride on said sheet or off said sheet laterally outwardly of said edge,

(f) first switch means cooperating with said first and second fingers to energize said control circuit to move said carriage outwardly, said first switch means being de-energized when said first and second fingers are both riding on said sheet, said first switch means being energized when said first finger is riding on said sheet and said second finger is riding off said sheet,

(g) second switch means cooperating with said third and fourth pile fingers to energize said electrical circuit to move said carriage inwardly, said second switch means being de-energized when said third and fourth fingers are both riding off said sheet, said second switch means being energized when said third finger is riding on said sheet and said fourth finger is riding off said sheet.

2. The invention according to claim 1 further comprising a third switch means cooperating with said first finger so that when said first finger rides off said sheet, said third switch means will energize said circuit to move said carriage outwardly, and fourth switch means associated with said fourth finger so that when said four-12h finger is riding on said sheet, said fourth switch means will energize said circuit to move said carriage inwardly.

3. The invention according to claim 2 in which said third switch means comprises first electrical contact on said first finger and a second electrical contact fixed on said finger mounting means which are normally open when said first finger rides on said sheet, but which close when said first finger rides off said sheet, said fourth switch means comprising a first contact on said fourth finger and a second contact fixed to the said finger mounting means, said contact being normally open when said fourth finger rides off said sheet but which are closed when said fourth finger rides on said sheet.

4. The invention according to claim 1 in which said first switch means comprises a first electrical contact on said first finger and a second electrical contact on said second finger adapted to dis-engage when said first and second fingers ride on said sheet, and to engage when said first finger rides on said sheet and said second finger rides off said sheet, said second switch means comprising a third electrical contact on said third finger and a four-uh electrical contact on said fourth finger which are normally disengaged when said third and fourth fingers are riding off said sheet, but which engage when said third finger rides on said sheet and said fourth finger rides off said sheet.

5. An edge sensing device for a sheet comprising:

(a) an electrical control apparatus for restoring a Work process to a predetermined condition,

(b) a sensing finger for determining the condition of said process,

(c) first switch means adapted to be opened by said finger when said predetermined condition has been established and to close said first switch means upon a deviation in said condition,

(d) a first electronic valve,

(e) means for normally biasing said first valve so it will not conduct,

(f) said first switch means being connected to said first valve to reduce said bias so said first valve will conduct,

(g) a second electronic valve,

(h) means for electrically connecting said first and second valves when said first valve is conducting,

(i) a time relay circuit in said coupling means to that said second valve will conduct at a predetermined time after said first and second valves have been coupled,

(j) second switch means communicating said second valve with said control apparatus whereby said second switch means will be energized to actuate said control apparatus after said second valve is conducting.

6. The invention according to claim 5 in which said first switch means is adapted to ground the biasing element of said first valve when said first switch means is closed.

7. The invention according to claim 5 in which said time delay circuit comprises an RC circuit and a potentiometer for adjusting the discharge time of said RC circuit.

8. The invention according to claim 7 in which said coupling means includes an electrical relay circuit connecting the anodes of said valves.

9. The invention according to claim 8 in which the anode of said second valve is connected to the biasing element of said second valve through said potentiometer and the resistor of said time delay circuit, and the capacitor of said RC circuit connects said biasing element to the cathode of said second valve.

10. The invention according to claim 9 in which the grid of said second valve is connected to said second switch means.

11. The invention according to claim 8 in which a positive voltage is applied to tr-he anode of said first valve and a negative voltage is applied to the cathode of said second valve and the biasing element of said first valve when said first switch means is open.

References Cited by the Examiner UNITED STATES PATENTS 1,186,906 6/1916 Hopkins 242-57.1 2,968,449 1/1961 Hajos 242-571 3,156,426 11/1964 Brock 22645 X vM. HENSON WOOD, JR., Primary Examiner.

w. F. MCCARTHY, Assistant Examiner. 

5. AN EDGE SENSING DEVICE FOR A SHEET COMPRISING: (A) AN ELECTRICAL CONTROL APPARATUS FOR RESTORING A WORK PROCESS TO A PREDETERMINED CONDITION, (B) A SENSING FINGER FOR DETERMINING THE CONDITION OF SAID PROCESS, (C) FIRST SWITCH MEANS ADAPTED TO BE OPENED BY SAID FINGER WHEN SAID PREDETERMINED CONDITION HAS BEEN ESTABLISHED AND TO CLOSE SAID FIRST SWITCH MEANS TO DEVIATION IN SAID CONDITION, (D) A FIRST ELECTRONIC VALVE, (E) MEANS FOR NORMALLY BIASING SAID FIRST VALVE SO IT WILL NOT CONDUCT, (F) SAID FIRST SWITCH MEANS BEING CONNECTED TO SAID FIRST VALVE TO REDUCED SAID BIAS SO SAID FIRST VALVE WILL CONDUCT, 